Thinning TSV wafers through back-grinding process improved through the use of novel coolant/lubricant/corrosion inhibitor, TENSOR HTD-3.
Recent laboratory tests from a research organization show that using a 100:1 mixture of H2O: TENSOR HTD-3 (compared to water only) yields a 73% reduction in micro-cracking and a yet to be defined reduction in sub-surface damage. Testing was performed using a course grind step followed by a fine grind step. Measurements were taken after fine grind only. Machine operating parameters were within accepted norms and normal removal rates were achieved grinding 200 mm single crystal silicon wafers simulating TSV structures.
Applicable to TSV processes which thin utilizing back-grind, TENSOR HTD-3 also protects Copper structures from corrosion, dishing and galling. Defects occurring within Cu vias are evident with “water only” processes due to the differences in hardness and machinability of copper versus silicon or silicon dioxide. However, it was found that copper defects can propagate defects in the surrounding crystal.
Galling and smearing of copper into the silicon material is possible when not optimizing the back-grinding process through the use of TENSOR HTD-3. Galling and smearing of copper metal within the silicon along with deeper micro-cracking can cause electrical failure downstream. These defects also put additional stress on final finishing processes, particularly CMP.
For additional information on TENSOR HTD-3 or other TENSOR Series products for the semiconductor industry, email Scovin@isurface.com